Radio-frequency identification (“RFID”) tags may be used to identify and track objects to which the tags are affixed. An RFID tag may work on a principle of electromagnetic induction, allowing the tags to be compact as well as, in at least some cases, eliminating the need for a battery to power the RFID tag. A serial number or other identifier may be stored on the tag. The identifier may be subsequently retrieved by bringing the tag and a reader device in relatively close proximity. RFID tags are used in a variety of circumstances, including those related to inventory tracking, identification of lost animals, and other purposes.